1. The Field Of The Invention
This invention relates to line tightening devices, and more particularly, to that class adapted to automatically provide tensioning forces to endless lines and to the free end of a non-endless line.
2. Description Of The Prior Art
The prior art includes a variety of methods adapted to increase the tensioning forces in clothes lines. U.S. Pat. No. 987,015 issued Mar. 14, 1911 to D. W. Rantine teaches a device tensioning an endless clothes line utilizing a beam adapted with a plurality of fixed cams on the uppermost surface thereof. An arm selectively engages a cam at one end supporting a clothes line pulley at the other end thereof. The user manually displaces the arm towards the supported end of the beam increasing the tension in the line thereby. U.S. Pat. No. 3,163,903issued Jan. 5, 1965 to F. R. Knaebe discloses a beam member adapted to be supported at one end, having a lateral line gripping surface parallel to the longitudinal axis of the beam. An opposing line grasping surface is secured to the beam utilizing a slot displaced angularly downwardly towards the line gripping surface. The line gripping surface tends to bind the line as the line tension increases. The free end of the line, however, may be pulled taut manually, easily overcoming the binding forces securing the line between the line gripping and line grasping surfaces. Both of the aforementioned patents require manual manipulation to increase the tension in the line. U.S. Pat. No. 1,096,662 issued May 12, 1914 to S. Zimmermann shows a pulling jack adapted to increase the tension in the line utilizing two rows of holes disposed along a beam member. Pins are selectively inserted in the holes providing a pivot point about which a manually operated arm may be pivoted. The jack increases the tension between a line fastened to one end of the beam and a line fastened to the arm intermediate the two rows of holes. This disclosure permits the increase in the tension between the lines in discreet steps manually obtained by the manipulation of the arm.